What is the difference between strong (in LLVM compiler) and persistence (in GCC compiler)?
strong - a new feature in the automatic calculation of control points iOS 5 (ARC), which behave the same as retain in iOS 4. Link to the article.
strong
retain
Also check out this other SO question: @property definitions with ARC: strong or persistent?
strong - a new keyword that was entered with the arc (automatic reference counting). This can be found in the bazillion if you are looking for google, including this http://cupsofcocoa.com/2011/11/27/the-jungle-part-4-automatic-reference-counting/